172 - Useful Links - a link becomes useful when it promotes further understanding on a topic. The problem you run into with this is that you don’t always know what level of understanding your future self will have on a subject matter. If you understand it really well down the line, then all the links you created become useless and distracting. If on the other hand, your level of prior knowledge on a topic is low then links that provide more information become very useful.
Related to concept of Utility